How to check if Zend Optimizer or Zend Guard Loader is installed

Through phpinfo you can see all kinds of php information. If you see this:

then it means you have Zend Engine. But what it doesn't say is whether you use Zend Optimizer or Zend Guard Loader.

How can you check if one of these is installed?

You can see whether Zend optimizer is installed by phpinfo like this:

Simply google for pictures "phpinfo zend optimizer" and you will get many results on what it looks like.